Machine tool with tool spindle and tool exchanger

ABSTRACT

A machine tool with a driven tool spindle that is rotatable about a spindle axis that includes a tool exchanger including grippers to displace tool-holders or tools between a receiver position in the tool spindle and a storage position, or vice versa. The tool-holders or tools in these two positions are identically oriented, and the storage position and the receiver position are displaced with respect to each other along the spindle axis direction of the tool spindle. The tool exchanger possesses a transport mechanism that includes a carrier element pivotable about a pivot axis inclined with respect to the spindle axis, to which grippers pivotable about axes perpendicular to each other are connected. Guide elements are mounted so they may be driven and rotate about the first axis parallel to the pivot axis in the opposite direction to the pivot direction of the carrier element are included on the carrier element. Each of these guide elements is connected with grippers so they may rotate about second axes extending parallel to the spindle axis.

TECHNICAL FIELD

The invention relates to a machine tool of the type including a toolexchanger.

BACKGROUND OF THE INVENTION

A machine tool of the conventional type disclosed in DE 196 00 055 A1includes a tool exchanger with longitudinal and latitudinal sparsconnected to a jointed rectangle via cross-spars, whereby thelongitudinal spars may be driven about axes parallel to one another. Theconventional solution requires a relatively large space that is oftennot available because of the close proximity to the tool spindle. Also,adequate stability may be achieved by the multi-part conventionalsolution only using large dimensions. The concomitant high weight limitsthe potential exchange speed.

A device for the transport of machine tools that includes a threaded rodconnected to a motor that moves along a fixed worm gear is also knownfrom DE 44 06 386 A1. The drive of the first threaded rod is connectedto a second threaded rod of the same transmission ratio. The secondthreaded rod is connected to a worm gear bearing the tool. Atransmission provided with a coupling is positioned between the twothreaded rods. Use of worm gear drives limits the displacement speed ofthe tool.

SUMMARY OF THE INVENTION

Based on this state of the art, it is the task of this invention tocreate a machine tool of the discussed type that includes aspace-saving, stable, and rapid tool exchanger.

The solution of this task derives from a machine tool, in accordancewith the present invention, comprising a tool spindle (1; 1′) rotatableabout a spindle axis (1 a) and a tool exchanger including at least onepivotable gripper (2; 2′) for displacing tool holders (4) or toolsbetween a receiving position in the tool spindle (1; 1′) and a storageposition or vice versa. The orientation of the tool holder (4) or toolsin the receiving and storage positions is identical, and wherein thestorage position and receiving position are displaced with respect toeach other along the direction of the spindle axis (1 a) of the machinetool (1; 1′).

The machine tool of the present invention also includes transportmechanism that includes a driven inclined carrier element (3; 3′)rotatable about a pivot axis (5) inclined to the spindle axis (1 a), towhich carrier element (3; 3′) and the at least one pivotable gripper (2;2′; 2″) are connected about mutually-perpendicular axes, and whereinguide elements (10) are included on and driven by said carrier element(3; 3′) that include a central drive gear wheel (3 a). The carrierelement (3; 3′) are mounted such that they may rotate about a first axes(8) that is parallel to the pivot axis (5) in the direction opposite toa pivoting movement of the carrier element (3; 3′) about the pivot axis(5). Each of these first axes (8) are connected to the at least onegripper (2; 2′; 2″) and wherein the at least one gripper rotates aboutsecond axes (9) extending parallel to the spindle axis (1 a).Thecomponents possess relatively low mass, so that the tool exchanger mayswitch rapidly. Only one rotatable carrier element is provided to whichgrippers are mounted and guided along their unalterable directions.

Advantageous embodiments of the invention may be derived from thedependent claims recited herein.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the present invention will bebetter understood by reading the following detailed description, takentogether with the drawings wherein:

FIG. 1 is a right side plan view of the machine tool with tool spindleand tool exchanger in accordance with the present invention;

FIG. 2 is a left side plan view of the machine tool with tool spindleand tool exchanger in accordance with the present invention;

FIG. 3 is a top plan view of the machine tool with tool spindle and toolexchanger in accordance with the present invention; and

FIG. 4 is a plan view of the machine tool with tool spindle and toolexchanger in accordance with the present invention;

DETAILED DESCRIPTION OF THE PRESENT INVENTION

In the figures, identical or similar-functioning parts are labeled usingidentical reference indices which may be distinguished from one anotherusing ′ or ″ marks. As shown in FIGS. 1-3, only one tool spindle 1 of amachine tool that may be rotated about a vertical spindle axis 1 a isshown, although this is not a limitation of the present invention. Themachine tool spindle 1 is mounted so that it may be displaced along thedirection of the spindle axis 1 a. The lower end of the machine toolspindle 1 includes at its lower end at least one known gripping device(not shown) in which the tool holder 4 may be gripped.

By means of a headstock (not shown) supporting the machine tool spindle1, a vertically-displaceable housing 12 is firmly connected with ajournal 12 b on which a carrier element 3 is mounted so that it mayswivel about a pivot axis 5. The pivot axis 5 is inclined with respectto the spindle axis 1 a. A gear wheel 12 a is firmly mounted on thejournal 12 b so that it may not rotate. The carrier element 3 is drivenby means of a bevel gear drive wheel 3 a firmly attached to the carrierelement 3. Drive is produced by a pinion gear 11 a firmly attached to adrive shaft 11 that meshes with the drive gear wheel 3 a.

Two grippers 2 are mounted on the carrier element 3 diametricallyopposed to each other that surround the tool holder 4 about its outercircumference, and which in turn are attached to a holder element 14.The holder element 14 is mounted opposite the carrier element 3 so thatit may pivot about two axes 6 and 7 perpendicular to each other. Theaxis 7 is formed by a bearing journal 14 a on the holder element 14 thatis mounted in a bracket 15 so that it may rotate. The bracket 15surrounds a gear wheel 10 a, and is in turn mounted to the carrier arm 3so that it may rotate about the axis 6.

The gear wheel 10 a is firmly attached to a guide 10 that is mounted onthe carrier element 3 so that it may rotate about a first axis 8extending parallel to the pivot axis 5. The gear wheel 10 a engages anintermediary gear wheel 13 mounted on the carrier element 3 so that itmay rotate, with the gear wheel 13 meshing with the central gear wheel12 a. As the carrier element 3 pivots, the intermediary gear wheel 13“see-saws” against the central gear wheel 12 a. The transmission ratiobetween the central gear wheel 12 a and the gear wheel 10 a attached tothe guide 10 is 1:1. Two intermediary wheels 13 are provided for the twogrippers 2 of the transport mechanism.

The bearing journal area of the guide 10 supported by the carrierelement 3 and supporting the gear wheel 10 a is inclined in a first areaperpendicularly downward. The guide 10 is crimped in crank fashion atits end opposite the bearing journal area, and forms a cog that ismounted in a bearing on the gripper 2 so that it may rotate.

During pivoting of the carrier element 3, the guide 10 is pivoted by thesame angle but in the opposite direction. Thus, the area of the guide 10in contact with the bearing journal area constantly maintains itsperpendicular orientation. In this manner, the gripper 2 pivots from itsinitial, upper position opposing a magazine (not shown) into a lowerposition facing the machine tool spindle 1 in which a tool holder 4 maybe received by the working-material spindle 1 via displacement along thespindle axis 1 a. The grippers 2 are aligned to each other during thispivoting.

For a tool exchange, a previously-used tool holder 4 is removed from thetool spindle 1 a by one of the grippers 2, and a tool holder 4 with anew tool is removed by the other gripper 2 from the storage magazine.After rotating through 180°, the tool holder 4 with the new tool islocated in the receiver position below the tool spindle, and the usedtool is in the storage position.

Vertical displacement motion of the entire mechanism for the raising orlowering to the spindle or magazine position is performed separately.

Regarding the embodiment shown in FIG. 4, the exchange procedure fortools or tool holders 4 described above in this second embodiment mayalso be used with a machine tool with two tool spindles 1′ and 1″extending parallel to each other. The tool exchanger includes a carrierelement 3′ on which four grippers 2′ or 2″ are mounted. One intermediarygear wheel 13′ or 13″ each meshes with two gear wheels 10 a′ or 10 a″,each of which is attached to a guide 10 in the manner described above.The grippers 2′ or 2″ are identical, and are implemented the same as inthe first embodiment. The gripper 2′ of the first pair and the gripper2″ of the second pair are arranged parallel to each other. During toolexchange, two tool holders 4 are simultaneously or non-simultaneouslyremoved from the two tool spindles 1′ and 1″, or are passed to them, andtwo tool holders 4 are pre-positioned into the storage position.

In the embodiment examples shown and described, the rotational movementof the guides is implemented with 1:1 transmission ratio viaintermediary gear wheels 13 or 13′ or 13″. A corresponding but oppositerotational movement of the guides with 1:1 transmission ratio may alsobe achieved using other suitable means, such as via toothed belts thatinteract with the gear wheels, or with chains that interact with chainpulleys.

In the illustrated embodiments, the spindle axis la is always positionedvertically. Instead, the spindle axis may also assume any otherdirection differing from the vertical direction, such as a horizontalalignment for a horizontal tool spindle, or a sharply-inclined directionfor an inclined tool spindle.

Modifications and substitutions by one of ordinary skill in the art areconsidered to be within the scope of the present invention which is notto be limited by the claims which follow.

What is claimed is:
 1. A Machine tool comprising: a tool spindle (1; 1′)rotatable about a spindle axis (1 a); a tool exchanger including atleast one pivotable gripper (2; 2′) for displacing tool holders (4) ortools between a receiving position in the tool spindle (1; 1′) and astorage position or vice versa, and whereby the orientation of the toolholder (4) or tools in the receiving and storage positions is identical,and wherein the storage position and receiving position are displacedwith respect to each other along the direction of the spindle axis (1 a)of the machine tool (1; 1′); and a transport mechanism that includes adriven inclined carrier element (3; 3′) rotatable about a pivot axis (5)inclined to the spindle axis (1 a), to which carrier element (3; 3′) andthe at least one pivotable gripper (2; 2′; 2″) are connected aboutmutually-perpendicular axes, and wherein guide elements (10) areincluded on and driven by said carrier element (3; 3′) that include acentral drive gear wheel (3 a), said carrier element (3; 3′) beingmounted so it may rotate about a first axes (8) that is parallel to thepivot axis (5) in the direction opposite to a pivoting movement of thecarrier element (3; 3′) about the pivot axis (5), each of these firstaxes (8) being connected to said at least one gripper (2; 2′; 2″)rotating about second axes (9) extending parallel to the spindle axis (1a).
 2. The machine tool as in claim 1, wherein the central drive gearwheel (3 a) is a component of a bevel gear drive.
 3. The machine tool asin claim 1, wherein the guide elements (10) driven about the first axes(8) opposite to the pivot motion about the pivot axis (5) includerotatable gear wheels (10 a; 10 a′ 10 a″).
 4. The Machine tool as inclaim 1, wherein the gear wheels (10 a; 10 a′ 10 a″) are coupled with acentral, fixed, non-rotatable gear wheel (12 a; 12 a′) of generally thesame diameter.
 5. The machine tool as in claim 1, wherein the couplingof the gear wheels (10 a; 10 a′ 10 a″; 12 a; 12 a′) is accomplishedusing intermediary wheels (13; 13′) mounted on the carrier element (3;3′) so that they may rotate.
 6. The machine tool as in claim 5, whereinthe axes (6 and 7) connecting each said at least one gripper (2; 2′) tothe carrier element (3; 3′) intersect with the first and second axes (8and 9) at a single point.
 7. The machine tool as in claim 1, wherein theguide elements (10) are crimped.
 8. The machine tool as in claim 1,wherein the tool exchanger includes two grippers (2) diametricallyopposed to the pivot axis.
 9. The machine tool as in claim 1, wherein itincludes two tool spindles (1′; 1″) that may be driven to rotate aboutthe spindle axes (1 a) extending parallel to each other, and wherein thetool exchanger includes four grippers (2′; 2″), two of which areidentically oriented.
 10. The machine tool as in claim 9, wherein thegear wheels (10 a; 10 a′ 10 a″) connected with the guide elements (10)of the two identically-oriented grippers (2′; 2″) mesh with a commonintermediary wheel (13′; 13″).
 11. The machine tool as in claim 10,wherein the opposing rotational motion of the guide elements (10) mayalso be realized at a 1:1 drive ratio using other drives such as, forexample, toothed belts or chains.